Simulation of Tip-Timing Measurements of a Cracked Bladed Disk Forced Response

Kharyton, Vsevolod; Lainé, Jean-Pierre; Thouverez, Fabrice; Кучер, О.

doi:10.1115/gt2010-22388

Cited by 8 publications

(4 citation statements)

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“…A somewhat similar approach is used in the simulators presented in [20,21], where the BTT data are synthesised from actual measurements using the minimum number of probes. It is also noted that FE-based simulators used in previous works (Khayrton [22], Diamond [23]) were limited to single mode resonance [24].…”

Section: Fig 1 Herementioning

confidence: 99%

An experimentally validated modal model simulator for the assessment of different Blade Tip Timing algorithms

Mohamed

Bonello

Russhard³

2020

Mechanical Systems and Signal Processing

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Blade Tip Timing (BTT) technology is concerned with the estimation of turbomachinery blade vibration. A BTT system comprises two parts: (a) measurement system for blade tip arrival times ("BTT data"); (b) the analysis algorithms. Simulators that generate BTT data play a key role in BTT development since they enable an assessment of the performance of the different BTT algorithms. Such assessments are not feasible with real engine data since they require controlled conditions and knowledge of the true tip vibration as the reference.Most simulators in the literature are based on a simple spring-mass-damper model and commercially available ones have no physical underpinning. This work presents a novel realistic simulator based on the experimentally validated Finite Element (FE) model of a bladed disk (blisk). Transformation to modal space enables the efficient generation of simulated BTT data regardless of the complexity of the blisk geometry. The simulator is then used in a first-time comparative study of three principal BTT algorithm methods (autoregressive, sine fitting, two-parameter plot) under various conditions involving synchronous and asynchronous excitations with both single and simultaneous frequencies.The study clarifies obscurities in the methods and demonstrates the applicability of each method to different BTT system scenarios.

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Section: Fig 1 Herementioning

confidence: 99%

An experimentally validated modal model simulator for the assessment of different Blade Tip Timing algorithms

Mohamed

Bonello

Russhard³

2020

Mechanical Systems and Signal Processing

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“…Indeed, it has been observed [7] that algorithms may work very well with data from simplistic simulators but fail to achieve sufficient accuracy with real data. It is also noted that FE-based simulators used in previous works (Khayrton [24], Diamond [25]) were limited to single mode resonance [26].…”

Section: Btt Simulatormentioning

confidence: 99%

A novel method for the determination of the change in blade tip timing probe sensing position due to steady movements

Mohamed

Bonello

Russhard³

2019

Mechanical Systems and Signal Processing

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The correlation of blade tip timing (BTT) measurements against strain gauge (SG) measurements and finite element (FE) predictions includes a number of uncertainties. One of the main ones is the steady movement of the blades (i.e. change in their mean position and orientation). This causes the sensing positions of the probes relative to a blade tip to deviate from their intended (nominal) positions, leading to deceptive results for the BTT amplitude and the corresponding stress levels.Such movements are caused by variations in static loading conditions (thermal and pressure) associated with changes in the operating speed. A novel method is introduced for the determination of three basic types of blade tip steady movements: axial; lean; untwist. The method relies on linking the shift in the averages of the BTT data to a number of geometrical relations, depending on the type of movement. Not more than two probes (to be placed at different axial positions) are needed to measure all three types of movement. The method is validated by simulations using a novel BTT simulator, and by measurements from both a test rig and real engine tests. The validated results demonstrate the great potential of the method for practical applications.

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“…The blade vibration frequency f 0 is an important parameter reflecting the health of a blade. It is often estimated by various methods [ 7 , 8 , 11 ]. However, the uncertainties between estimated value

and the original one f 0 may cause a severe reconstruction error.…”

Section: Numerical Simulationsmentioning

confidence: 99%

A Non-Uniformly Under-Sampled Blade Tip-Timing Signal Reconstruction Method for Blade Vibration Monitoring

Lin

Chen

et al. 2015

Sensors

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High-speed blades are often prone to fatigue due to severe blade vibrations. In particular, synchronous vibrations can cause irreversible damages to the blade. Blade tip-timing methods (BTT) have become a promising way to monitor blade vibrations. However, synchronous vibrations are unsuitably monitored by uniform BTT sampling. Therefore, non-equally mounted probes have been used, which will result in the non-uniformity of the sampling signal. Since under-sampling is an intrinsic drawback of BTT methods, how to analyze non-uniformly under-sampled BTT signals is a big challenge. In this paper, a novel reconstruction method for non-uniformly under-sampled BTT data is presented. The method is based on the periodically non-uniform sampling theorem. Firstly, a mathematical model of a non-uniform BTT sampling process is built. It can be treated as the sum of certain uniform sample streams. For each stream, an interpolating function is required to prevent aliasing in the reconstructed signal. Secondly, simultaneous equations of all interpolating functions in each sub-band are built and corresponding solutions are ultimately derived to remove unwanted replicas of the original signal caused by the sampling, which may overlay the original signal. In the end, numerical simulations and experiments are carried out to validate the feasibility of the proposed method. The results demonstrate the accuracy of the reconstructed signal depends on the sampling frequency, the blade vibration frequency, the blade vibration bandwidth, the probe static offset and the number of samples. In practice, both types of blade vibration signals can be particularly reconstructed by non-uniform BTT data acquired from only two probes.

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Simulation of Tip-Timing Measurements of a Cracked Bladed Disk Forced Response

Cited by 8 publications

References 0 publications

An experimentally validated modal model simulator for the assessment of different Blade Tip Timing algorithms

An experimentally validated modal model simulator for the assessment of different Blade Tip Timing algorithms

A novel method for the determination of the change in blade tip timing probe sensing position due to steady movements

A Non-Uniformly Under-Sampled Blade Tip-Timing Signal Reconstruction Method for Blade Vibration Monitoring

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